Two. One to change it and one to yell "Ta-daa!" when he's done.
A: None: Taureans don't like to change anything.
none. That's a hardware problem but have you tried turning it on and off again
Sikhs.
Answer is 2. One to change the lightbulb while the other screams "REPOST"
Get another one to yell BINGO
An old man yelling at the cloud
Phillip